The most prominent and best studied example for a zeolitic material with U.S.C. a BEA framework structure is zeolite Beta, which is a zeolite containing SiO2 and Al2O3 in its framework and is considered to be one of the most important nanoporous catalysts with its three-dimensional 12-membered-ring (12MR) pore/channel system and has been widely used in petroleum refining and fine chemical industries. Zeolite Beta was first described in U.S. Pat. No. 3,308,069 and involved the use of the tetraethylammonium cation as the structure directing agent. Although numerous alterations and improvements had since then been made to the preparation procedure, including the use of other structure directing agents such as dibenzyl-1,4-diazabicyclo[2,2,2]octane in U.S. Pat. No. 4,554,145 or dibenzylmethylammonium in U.S. Pat. No. 4,642,226, the known processes for its preparation still relied on the use of organic template compounds. In U.S. Pat. No. 5,139,759, for example, it is reported that the absence of an organic template compound in the synthetic procedure of zeolite Beta leads to the crystallization of ZSM-5 instead.
Recently, however, it has surprisingly been discovered that zeolite Beta and related materials may be prepared in the absence of the organotemplates which until then had always been used as structure directing agent. Thus, in Xiao et al., Chem. Mater. 2008, 20, pp. 4533-4535 and Supporting Information, a process for the synthesis of zeolite Beta is shown, in which crystallization of an aluminosilicate gel is conducted using zeolite Beta seed crystals. In WO 2010/146156 A the organotemplate-free synthesis of zeolitic materials having the BEA framework structure, and in particular to the organotemplate-free synthesis of zeolite Beta is described. In Majano et al., Chem. Mater. 2009, 21, pp. 4184-4191, on the other hand, Al-rich zeolite Beta materials having Si/Al ratios as low as 3.9 are discussed which may be obtained from reactions employing seeding in the absence of organic templates. Besides the considerable advantage of not having to use costly organotemplates which required subsequent removal from the microporous framework by calcination, the new organotemplate-free synthetic methodologies further allowed for the preparation of Al-rich zeolite Beta with unprecedentedly low Si/Al ratios.
Although notable progress has been made in the recent past with respect to the synthesis of new zeolitic materials having the BEA framework structure, there still remains a considerable need for the provision of new zeolitic materials having improved characteristics. This applies in particular in view of the numerous catalytic applications in which they are currently used. In this respect, WO 97/48665 A1 and the references cited therein might be mentioned, wherein the highly advantageous and particularly preferred use of zeolite Beta as a catalyst in a process for the acylation of an aromatic compound is described. Furthermore there is an ongoing need in the development of new and improved zeolitic materials which may advantageously be employed in existing and future catalytic applications.